1. Technical Field
The present invention relates to a driver, an electro-optical device, an electronic device, and the like.
2. Related Art
A driver that drives a display panel (e.g., liquid crystal display panel) causes an image corresponding to input display data to be displayed on the display panel by driving a display panel based on this display data. For this kind of image display, a method is available that displays a frame region around an image and improves the appearance of the image displayed within the frame region. The frame region is provided on the upper, lower, left, and right sides of the image so as to have a predetermined width (e.g., several pixels), and is displayed in black or white, for example. In the case of a driver having an embedded display memory, the content stored in the display memory may possibly change due to the influence of noise in an environment with a large amount of noise as in the case of an on-vehicle display or the like. For this reason, for the purpose of noise resistance, the data of the displayed image and the frame region needs to be regularly rewritten (refresh processing). JP-A-2002-354229 is an example of related art.
When displaying the frame region using a simple driver that does not have the display memory, data including frame region data is input from a host controller. On the other hand, the driver having an embedded display memory can accept a refresh processing command and internally write the frame region data in the display memory.
When thus performing the refresh processing in accordance with the command, a problem arises in that instructions given by the host computer are complicated. The host computer gives an instruction to perform the refresh processing by designating addresses of the display memory corresponding to the frame region and issuing the command. For example, if addresses of a starting point and an end point are designated, it corresponds to designation of a rectangle, and accordingly the frame region needs to be divided into four rectangles. That is to say, address designation and command issuance need to be repeated four times, resulting in complicated instructions. Furthermore, while the driver is refreshing one rectangle, the host controller needs to wait for the next command, and accordingly the load on the host controller increases.